Embodiments of the present invention are related to a linkage for use with an actuator that extends when activated. The linkage is compact and circular in shape which makes it especially useful with bellows and piezoelectric actuators. Embodiments of the invention are particularly useful in valves intended for proportional, or modulating, control of fluid delivery within industrial processes making semiconductor devices, pharmaceuticals, or fine chemicals, and similar fluid delivery systems.
Using piezoelectric actuators in normally closed proportional valves for high purity fluid delivery in semiconductor capital equipment is known. Typical designs transmit actuator motion to the movable elements inside such valves through relatively complicated mechanisms comprised of many separate pieces which often are costly to make. Mechanical assemblies having more than a dozen individual parts are common and often involve cross drilling through cylindrical elements, several separate springs and pins, truncated or polygonal shapes, and so forth. For example, U.S. Pat. No. 8,181,932B2 issued to Matsumoto, et al., includes a disc-shaped first preload jig having two parallel chordal through-holes capturing coupling pins which project through corresponding radial holes in a tubular actuator box and a concentric second preload jig. Another example, Japanese Patent No. 4119109 (discussed as prior art within U.S. Pat. No. 9,163,743 issued to Hidaka, et al.) includes a support cylinder made from Invar material having diametrically opposite arch-shaped radial openings which accommodate inserted hat-shaped semicircular split base pieces. Another example, U.S. Pat. No. 9,625,047B2 issued to Hirose, et al, includes a lower support cylinder within which a support frame is horizontally disposed through notches (in the support cylinder walls) and threaded items are secured with locking screws having hexagonal internal openings (typically made by broaching processes).